The present invention relates to a toy building set with toy building elements which have coupling studs and corresponding cavities to receive coupling studs on other building elements in frictional engagement.
GB 1 269 755 discloses a toy building set of the present type. In the cavities of the building elements there are two resilient walls or tongues in parallel with two outer walls. Cylindrical coupling studs on another building element can be received in the cavity such that they are in frictional contact with an outer wall as well as one of the resilient walls in the cavity. Projecting guide ribs are provided on the inner sides of the outer walls to ensure that coupling studs assume specific positions in the cavity.
U.S. Pat. No. 5,795,210 (see FIGS. 11 and 12) discloses building elements where the user, by orienting two building elements differently relative to each other, can choose to engage or disengage supplementary coupling means and thereby deliberately choose a xe2x80x9cnormalxe2x80x9d coupling force or an increased coupling force between interconnected building elements.
These documents do not disclose coupling means with different friction against coupling means like in the present invention.
U.S. Pat. No. 3,005,282 discloses toy building sets with building elements, which are marketed under the trademarks LEGO and DUPLO.
FIGS. 1 and 2 show such a known toy building set 10 seen in perspective from above and from below, respectively. This known toy building element has a square horizontal cross-section with four vertical, outer walls 11 and a horizontal upper wall 12 which, together with the outer walls, defines a cavity 13 which accommodates a central tube 14 extending from the inner side of the upper wall. The upper side has four cylindrical coupling studs 15 which, as described in the above-mentioned U.S. Pat. No. 3,005,282, may be received in the cavity 13 of a corresponding building element so that that the coupling studs 15 are in frictional contact with the inner sides of the outer walls 11 and with the tube 14, which is also called a coupling tube.
FIG. 3 shows another known toy building element 16 seen from below, where the upper side of the element has cylindrical building studs (not shown) arranged in four rows perpendicular to each other with four coupling studs in each row. This building element has four outer walls 17 and a square outer shape. The four walls define a cavity 18 in which there are partitions 19 that divide the cavity into four subcavities. Each of the four subcavities accommodates a cylindrical coupling tube 20, and a central coupling tube is provided in the centre where the partitions 19 meet. All these coupling tubes extend from the lower side of the upper wall 21 of the building element, which forms a termination or a ceiling of the cavity 18.
The known building elements like in FIG. 3 and corresponding, larger building elements may be built together in the same manner as the building element 10 in FIGS. 1 and 2. Coupling studs on one of the elements 16 are received in the cavity 18 of another element, so that coupling studs are in frictional contact with the inner sides of the outer walls 17 and/or with one or two of the tubes 20 in the cavity. The partitions 19 in the cavity 18 are thinner than the outer walls 17, which means that coupling studs will not be in frictional contact with the partitions.
Consequently, only the coupling studs which are in contact with the outer walls at their corners have full friction, i.e. the same total friction as is the case with building elements in FIGS. 1-2, while coupling studs which are spaced from the corners and coupling studs having no contact with outer walls each have a smaller total friction. The total friction is here the frictional force, which must be overcome to assemble or to disassemble two building elements, and this force is therefore also called the coupling force.
This is intended by the known building elements, which have an upper side with 4xc3x974 or more coupling studs. If the cavities of these known building elements were not arranged as described, but so that all 4xc3x974 coupling studs had full friction in the cavity, then the total coupling force would be correspondingly greater than with two elements like in FIGS. 1-2, and it would thereby take a correspondingly greater force both to assemble and to disassemble them. It would therefore be difficult for children to assemble and disassemble large building elements having many coupling studs. It is therefore intentional that the partitions are formed such that coupling studs will not be in contact with the partitions, so that coupling studs in only some positions have full coupling force, while coupling studs in other positions have a reduced coupling force. This provides the advantage that children can easily assemble and disassemble even large toy building elements with many coupling studs.
Still, the known building elements like in FIG. 3 have a drawback. FIG. 3 moreover schematically shows the known building element 10 in FIGS. 1 and 2 with its four coupling studs 15 received in the cavity in the other known, larger building element so that none of the four coupling studs 15 is in contact with the outer walls 17. The four coupling studs 15 are here in contact with the central coupling tube in the cavity, as this coupling stud is positioned coaxially with the coupling tube 14 in the element 10. It will be seen that the building element 10 can rotate about the coupling tube between limits determined by the engagement of the coupling studs with the thin partitions 19, which thus serve as end stops for the rotation. Therefore, the two building elements thus built together are not fixed, but can rotate relatively to each other. Correspondingly, building elements with one, two or three coupling studs, all of which are in contact with the outer side of one and the same coupling tube, will be able to rotate.
The object of the invention is to remedy this drawback, or in other words to provide a toy building set where relatively large building elements may be built together in such a manner that the coupling force is essentially the same as for the known relatively large building elements, while a smaller building element is essentially fixed so that it cannot rotate when it is built together with a larger element.
This object is achieved by a building set according to the invention where guide means are arranged in the cavity, which restrict the movability of the coupling studs in the cavity, and which just have an insignificant friction against the coupling studs.